1. Field of the Invention
This invention pertains to the field of computer input devices and in particular pertains to input devices having multi-directional detection devices for providing multi-dimensional input to a computer to control operation of computer software.
2. Description of the Related Art
A computer user operates an input device to control software operating in a computer. The input device provides input signals to the computer program which then operates in a programmed manner in response to the input signals.
A keyboard is a common input device in which depressing a key sends a signal to the computer. Software decodes the signal and produces a character on the display or initiates a programming sequence. A keyboard is a collection of one-dimensional input devices because each key can only provide a single input. For example, the cursor keys on a keyboard can move an on-screen cursor in a single direction, but not simultaneously in two directions.
A two-dimensional input device can provide signals to a computer to simultaneously control two dimensions, or software variables. An early two-dimensional input device that is still in common use today is known vernacularly as a mouse. In basic terms a mouse is a palm-sized housing that surrounds a rubber-coated ball which protrudes from a flat, bottom surface of the housing. Transducers within the housing detect rotation of the ball in two directions. When the mouse is placed on a desk, the ball likewise rests on the desk and motion of the mouse housing on the desk causes the ball to rotate within the housing and move the transducers. The transducers translate the ball's rotation into electrical signals that are provided to a computer. By moving the mouse on a surface, such as a desktop, a user may control aspects of a computer program, such as an on-screen cursor. One or more buttons are located on top of the housing that can be depressed to further control the computer software.
A mouse is a relative pointing device because there are no defined limits to the mouse's movements and because its placement on a surface does not map directly to a specific screen location. The mouse is two-dimensional because the mouse has a two-direction detection device that can detect mouse movement along two directions simultaneously and provide two-dimensional input to a computer. For example, a mouse may move a computer display cursor in two dimensions (e.g., vertically and horizontally) simultaneously.
Input devices are a means by which a computer user provides input signals to a computer. The processing of the input signals is determined by the computer software operating when the signals are received. Thus, different computer applications use input device signals in different ways.
Drafting programs accept mouse input to control a size or location of lines, or other features such as doors and windows. Games and simulations use mouse input to navigate through an on-screen environment. Moving the mouse over a physical, horizontal desktop is translated to motion in a virtual, vertical X-Y Cartesian surface on a computer display.
However, if a computer simulation requires movement in more than two dimensions, the two-dimension input device presents limitations. A known solution uses a mouse or keyboard button to toggle between two coordinate systems. For example, to use a mouse to control flying through three dimensional X-Y-Z space may provide that the mouse, in default mode, controls motion in the X-Y plane and pressing a button allows the mouse to control movement in the Y-Z plane. This system converts the mouse between coordinate systems--it does not permit simultaneous input in more than two-dimensions.
Other computer input devices include a touch sensitive pad, a trackball and a joystick. The touch pad is a flat panel that detects a user's finger on its surface and provides input signals to a computer. A trackball has a housing with a spherical ball protruding from a top surface of the housing. A user can directly manipulate the ball; transducers sense rotation of the ball and provide two-dimensional input signals to a computer. A joystick has a base with a protruding elongate member that pivots about its connection to the base; sensors detect the member's pivot and provide corresponding input signals to a computer.
At least one input device seeks to provide a combined mouse and trackball. U.S. Pat. No. 5,063,289 discloses a housing that captures a single, rotatable ball that protrudes from the housing. The ball is coupled to transducers that detect relative rotation of the ball and provide input signals to a computer in a conventional manner. The device of the '289 patent can be converted between a mouse and a trackball by inverting the device and adjusting a cover portion to accommodate the desired use. Though convertible, the device of the '289 patent provides signals comparable to a conventional mouse or trackball. This device does not provide more than a two-dimensional input.
Accordingly, the prior art does not provide an input device having a multi-dimensional signal that provides input of more than two-dimensions simultaneously.